Eyepieces for dso with an 8 inch dobsonian

[samjl22]

I bought an 8 inch dobsonian a few months ago and have seen many great things with it but now i think its time to upgrade my eyepiece. I really enjoy looking at deep sky objects so which eyepieces should i look into? I have a budget of around £120 and would like at least 2 decent ep's. Any suggestions would be really helpful.

[rory]

http://www.skystheli... eyepieces.html

skies the limit above, have starguider/bst eyepieces , which you could get two for under £100. 60* fov. very good e/p's for the money.

as for focal lengths for dso work . well it can vary alot upon the object viewed and conditions ect. but alot of my dso observing uses between 18mm and 12mm .

the starguider come in these focal lengths. - 5mm-8mm-12mm-15mm-18mm and 25mm..

IF you have a barlow consider carefully and double your arsenal. so a 18 and 12 , would also give you a 9 and 6 mm .

welcome to the forums by the way .

[Stargazer_00]

you want an 18mm BST for DSOs and an 8mm BST in my opinion. and then save for either a 5mm or 12mm depending on which way you think you need to go.

[Qualia]

It's my own personal prejudice, but I've found my most used EPs for general DSO viewing (not open clusters) have always been around that 120x mark and then backing off from that with something around 90x. The former will give you exit pupil of around 2mm and the latter around 2.8mm. If you get a 25mm , you'll have a nice finder EP and one useful for open clusters and if you got yourself a decent barlow with just these 3 EPs you'd have a nice spread like this:

25mm / 12.5mm = 48x, 96x.
14mm / 7mm = 85x, 170x.
10mm / 5mm = 120x / 240x.

The lower mags would be ace for general hunting and framing largish objects, the middle ground for globs, galaxies, nebulae, the more limited higher range for Saturn, Jupiter and Lunar work and the 240x for those exceptional nights with Saturn or the Moon. If you got yourself some Baader solar filter, your 48x would be also be fine for white light sun observations.

The only snag in this plan is not knowing whether planets are your thing. If they were, you might want a bit of a spread around 130x to 200x.

Hope that helps.

[Paul81]

I would echo some previous comments, in general for DSO I tend to mostly use my 13mm Ethos (about 92x in my scope), approx 100x is a great magnification for a lot of DSOs. I do tend to go higher for planetary nebula (8mm). Naturally as well you need to consider the apparent field of view. Also worth considering is exit pupil - of particular note is if you are on the fringe of needing glasses (like myself) due to slight astigmatism, depending on the severity and the exit pupil of the eyepiece, you might not need to wear glasses whilst observing.

To be fair its possible to over analyse these things! :-) I found the articles on the TeleVue website quite informative and a worth a read if you want more technical detail (I am an engineer so goes with the territory..)

Regardless of what ever glass you go for... its a slippery slope...!

[Stargazer_00]

It might just be me, but for planets I pretty much start as high as possible everytime and then bring it back if i cant tolerate the seeing. i dont build up to it, always start high!

[Schorhr]

As Qualia posted those magnification levels are a great range! The 66deg eyepieces are pretty decent and much more fun then Plössls or the included "Super" eypieces that many telescopes come with.

They are available from 26gbp and in 6, 9, 15 and 20mm. Together with a cheap achromatic barlow that's pretty decent as the next step up are eyepieces that cost at least three times as much.

A 30mm-35mm eyepiece is great for the overview, but depends on the aperture ratio & focal length of the telescope and the dark sky condition.

[Stargazer_00]

I'd still advise BSTs everytime. They perform like £100 eyepieces. In fact some retailers do sell their branded version of this eyepiece for that much.

[Schorhr]

Below 6mm I use some 60deg eyepieces as well, they are real nice and perform well on planets! Though the 66/70deg are not bad either. I guess it boils down to budget and the magnification levels desired.

[KevUU]

Another BST fan here.

My feeling is 12mm is a great workhorse, 25mm would be a good finder/wide(ish)-field, and 8mm is really nice too.

As for which two? If you barlow, 25 doubles to 12.5 anyway. But then if you like planetary the 12 will barlow to 6 which is awesome. I suspect you don't have a barlow though, if you have the Skywatcher (200p)? If I had to choose I'd say 25 first with a 12 or 8, and expect the other to follow soon

In summary, BST = good, dive in and see what you think and go from there

[alan potts]

Plus 1 for Qualia's well thought out answer.

Alan

[twotter]

I like to use my 21mm Hyperion, with the 14 & 28mm fine tuning rings. This gives four focal lengths 21, 17.6, 15.5 and 14mm. The 21mm gives a lower mag for a wider view. I sometimes miss those really faint fuzzies with my 31mm or 24mm so the 21mm is a good option for me. The fine tuning rings give that extra bit of flexibility for viewing a variety of other targets.

[russ.will]

There's a coupleof threads pointing these out already, but a £150 would land you one of these and one of these, delivered to your door with change to spare. They're basically Meade 5000 Series SWAs and therefore closely related to the ES68 EPs too.

I'm normally a bit wary about clones, but they're being sold by Explore Scientific (EU) who now own what was Meade Europe. ES are majority owned by JOC, who make both Meade and ES eyepieces, so it's unlikely that they would sell a substandard clone through their own outlets.

As to those two choices - Well a decent 24mm widefield EP is a joy in any scope, particulary a Newt/Dob and the 16mm is a decent step up in magnification for smaller DSOs, Globs, etc. My reason for suggesting the 24mm instead of the 28mm, is that it's the widest field EP you can fit in the 1.25" EP. A bit further down the line, if you add a good budget barlow like the GSO/Revelation 1.25" 2.25x 3 element APO (£38ish) you will have 24, 16, 12 & 8mm focal lengths, giving you 50, 75, 100 & 150x magnifications which is pretty handy spread. I've assumed you have a typical 200mm F6 Dob.

As a long term goal, something in the 32mm(ish) focal length in a 2" barrel like the 32mm SW Panaview is a worthy addition, but I personally think the two above will make a fine start to a robust EP collection.

Russell

[yanello]

On ‎5‎/‎7‎/‎2013 at 15:13, Qualia said:

It's my own personal prejudice, but I've found my most used EPs for general DSO viewing (not open clusters) have always been around that 120x mark and then backing off from that with something around 90x. The former will give you exit pupil of around 2mm and the latter around 2.8mm. If you get a 25mm , you'll have a nice finder EP and one useful for open clusters and if you got yourself a decent barlow with just these 3 EPs you'd have a nice spread like this:

25mm / 12.5mm = 48x, 96x.
14mm / 7mm = 85x, 170x.
10mm / 5mm = 120x / 240x.

The lower mags would be ace for general hunting and framing largish objects, the middle ground for globs, galaxies, nebulae, the more limited higher range for Saturn, Jupiter and Lunar work and the 240x for those exceptional nights with Saturn or the Moon. If you got yourself some Baader solar filter, your 48x would be also be fine for white light sun observations.

The only snag in this plan is not knowing whether planets are your thing. If they were, you might want a bit of a spread around 130x to 200x.

Hope that helps.

I appreciate this focus on the low, medium and high, with a barlow to boot. I just bought 14mm ES 82, and plan to barlow it. I have a 28mm, and a 10mm (both stock with the XT8 plus). So If I upgrade the low and high power, I will get about a 25 or so, and a 10mm. Good evening, Pat

[Charic]

I bought my Panaview specifically to look at M31.

The larger field of view makes  a difference  under the right conditions,  away from home and street lights!

For a Skyliner 200p Dob, I would start with an eyepiece that matches the focal ratio of the scope. A 6mm EP provides 1mm exit  pupil and 200x power. A 12mm has twice the exit  pupil, with half  the power, a good option for the Skyliner, then a wide field  of choice to closely  match your dilated pupil ( focal ratio X pupil mm ) That's 30mm for my eyes, but I use a 32mm?

There's  no definate focal length to have/own, just find what suits you best. My EPs are very  affordable  in the UK, and work  very well. I have several EPS from 3-32,  I use them all, the Panaview  is my  widest wide field, the 8mm Starguider was the 1st  of the set, and my cheapest EPs, Revelation Astro, are surprisingly good plossl's for about  £15, how can they be this good for so little money? I'd hoped to have owned  a Meade set and did not like the short eye relief of the Televue 8mm plossl so would not have owned the full set, but the Astrid work well for my needs.

Your eyes  may differ with the results I achieve, but hopefully you will find what suits you best. 

[billyharris72]

Another option would be the Celestron Ex-Cels, at about £60 each. I'd go for lower mags, personally, maybe a 25 and an 18mm. A Barlow will double those mags and you can extend your eyepiece collection towards the shorter focal lengths as you go along.

[Louis D]

Since no one has explicitly mentioned it, globular clusters take power very well in an 8 inch dob.  I usually use between 150x and 200x on them with great success.  Below that, they don't break up into individual pinpoints.  Much above that, and the exit pupil starts getting too small to enjoy the view.

[CraigT82]

I've just got myself a 9mm EP specifically for globs. In my 200p it gives 133x and I call it the glob buster! On good nights this combo will resolve hundreds upon hundreds of stars right to the core. 

My other DSO eps are a 12.5mm, 24mm and 32mm.

If I was starting from scratch and had £120 for two EPs for DSOs. I would definitely go for a couple of BSTs, probably 12mm and 18mm (assuming you already have stock 10mm and 25mm).  Alternatively, if you don't mind s slightly narrower field of view, a couple of Badder classic orthos would make fine DSO EPs. Say the 10mm for globs and 18mm for nebulae and the like?